Now it’s official: George Clooney is to marry his British-Lebanese fiancée in a civil ceremony in Venice town hall on Monday.

In a notice on Thursday featuring the tantalising words ‘matrimonio George Clooney’, the city council gave its first, understated acknowledgement of the hugely-anticipated A-list shindig set to take place amid its canals and palazzi in coming days.

But a gushing message of greeting to the happy couple this was not. Rather, it was a terse order notifying locals of the city’s intention to close the streets around the town hall to pedestrians from midday until around 2pm on Monday.

Due to concerns over public safety and circulation caused by the large numbers of people expected to be “drawn by the event’s star quality”, it said, police had requested restrictions to be put in place around Ca’ Farsetti and Ca’Loredan, the historic buildings which house the council. The main stretch affected, the Riva del Carbon, runs alongside the Grand Canal.

Ever since the 53-year-old actor and filmmaker was reported to have declared earlier this month that he and human rights lawyer Amal Alamuddin, 36, would be tying the knot “in a couple of weeks, in Venice, of all places”, the wedding has been the subject of huge speculation in the celebrity media.

The precise arrangements are being kept under wraps due to strict confidentiality agreements, but according to Italian reports the main reception is to take place on Saturday at the “7-star” Aman Canal Grande resort and is to be attended by a select group of startlingly stellar guests including Angelina Jolie, Brad Pitt and Matt Damon.

Under Italian law, however, civil ceremonies have to take place in council buildings, and it will be on Monday that the couple will be officially declared husband and wife.

Walter Veltroni, the former centre-left mayor of Rome and old friend of Clooney, is reported to be officiating.

A spokeswoman for Venice council said: “We cannot give any information because this is all covered by privacy [regulations].”